Maximization of wave motion within a hydrocarbon reservoir for wave-based enhanced oil recovery
Maximization of wave motion within a hydrocarbon reservoir for wave-based enhanced oil recovery
复制标题
最大化碳氢化合物储层内的波浪运动，以实现基于波浪的提高采收率
DOI：
10.1016/j.petrol.2015.03.009
复制
发表时间：
2015
影响因子：
--
通讯作者：
A. Fathi
中科院分区：
文献类型：
--
作者：
C. Jeong;L. Kallivokas;S. Kucukcoban;W. Deng;A. Fathi
我们讨论了一种系统的方法，通过将波能最佳地引导到感兴趣的区域，来研究动员困在目标储集区孔隙空间内的油滴的可行性。其动机来自现场和实验室的观察，这些观察提供了充分的证据，表明基于波的油藏刺激可以带来经济上可行的石油开采。使用受控的主动面波源，我们首先描述了识别能够最大化所需运动度量(动能、质点加速度等)的最佳波源信号所需的数学框架。在感兴趣的目标区域。我们使用偏微分方程组(PDE)约束优化的方法来描述相关的反震源问题，并使用最先进的数值波浪模拟工具来数值求解相关的离散反问题。以一个以浅层油藏为特征的合成地下模型的数值实验表明，优化器收敛到能够最大化水库内运动的波源信号。波源的频谱主要由地层的放大频率决定。我们还表明，波能可以集中在目标储集层区域内，同时将对邻近地层的干扰降至最低--这一概念也可以用于水力压裂作业。最后，我们将在储集层规模上进行的数值实验结果与颗粒水平上的半解析研究结果进行了比较，得出结论：对于浅层目标，优化的波源可能会动员捕获的油滴，从而提高石油采收率。
We discuss a systematic methodology for investigating the feasibility of mobilizing oil droplets trapped within the pore space of a target reservoir region by optimally directing wave energy to the region of interest. The motivation stems from field and laboratory observations, which have provided sufficient evidence suggesting that wave-based reservoir stimulation could lead to economically viable oil recovery.Using controlled active surface wave sources, we first describe the mathematical framework necessary for identifying optimal wave source signals that can maximize a desired motion metric (kinetic energy, particle acceleration, etc.) at the target region of interest. We use the apparatus of partial-differential-equation (PDE)-constrained optimization to formulate the associated inverse-source problem, and deploy state-of-the-art numerical wave simulation tools to resolve numerically the associated discrete inverse problem.Numerical experiments with a synthetic subsurface model featuring a shallow reservoir show that the optimizer converges to wave source signals capable of maximizing the motion within the reservoir. The spectra of the wave sources are dominated by the amplification frequencies of the formation. We also show that wave energy could be focused within the target reservoir area, while simultaneously minimizing the disturbance to neighboring formations – a concept that can also be exploited in fracking operations.Lastly, we compare the results of our numerical experiments conducted at the reservoir scale, with results obtained from semi-analytical studies at the granular level, to conclude that, in the case of shallow targets, the optimized wave sources are likely to mobilize trapped oil droplets, and thus enhance oil recovery.